Vehicle actuated traffic signal



July 3, 1934. J PETERSON 1,965,430

VEHICLE ACTUATED TRAFFIC SIGNAL Filed April 12, 1932 F'igi Inventor: Justin Peterson,

His Attor'neg.

Patented July 3, 1934 UNITED sTATEs VEHICLE ACTUATED TRAFFIC SIGN AL Justin Peterson, Lynn, Mam, assignor to General Electric Company, a corporation of New York Applicatlon April 12, 1932, Serial No. 004,141

T .z Claims. (01. 171-429) The present invention relates to trafllc signals of the type comprising a treadle located in the roadway which, when a vehicle passes over it, closes an electric circuit to eflect actuation oi the 6 lamps or other devices which signal to traflic the right of way. I

The object of my invention is to provide an improved construction and arrangement in apparatus of this type, and for a consideration of what I believe to be novel and my invention; attention is directed to the following specification and the claims appended thereto.

In the drawing, Fig. 11s a diagrammatic view of a road intersection provided with a trafiic actuated signalling arrangement; Fig. 2 is a. transverse sectional view of a treadle, and Fig. 3 is a wiring diagram.

Referring to Fig. 1 of the drawing, 1 indicates a road intersection provided with a signalling device 2 of any suitable type for directing traffic through the intersection. It may comprise, for example, red, amber and green signal lights arranged to be operated to direct trafflc along the trailic lanes which are indicated E, W, N and S. Located in each traflic lane at its right hand side is a vehicle actuated device or treadle 3, one 01 which is shown in section in Fig. 2. Vehicle actuated devices 3 are connected by cables indicated at 4 to a control box 5 in which is located suitable mechanism ior controlling the signal lights 2 to which it is connected by a cable indicated at 6. A portion of the final mechanism contained in casing 5 comprises parts shown in Fig. 3 as hereinafter described.

Referring to Figs. 2 and 3, the vehicle actuated device 3 comprises an electrical condenser A of suitable capacity embedded in the roadway and adapted to have its capacitance varied by, 9. vehicle passing over it. It may comprise two or more metal plates 7 suitably spaced apart and embedded in a rubber envelope or casing 8 which in turn may be held in a metal casing 9. 10 indicates the bed 01' the roadway.- When a vehicle passes over the device, its wheels will depress the rubber casing, moving plates 7 closer together and thus changing the capacitance of the device.

Electrical condenser A is connected by conductors 11 and 12 to a source of alternating current 13, here shown as the secondary winding of a relay device 14 for effecting actuation of control mechanism for the signals 2. The details of the control mechanism for the signals is not shown as its specific structure forms no part oi the present invention. For the purposes of this invention it may be taken to comprise circuit 15 which is opened when relay device 14 is energized, opening'ot such circuit serving to set into operation any suitable timing mechanism for the signals. The relay device is connected to the condensers through an electric valve 16 which serves as a relay controlling the circuit of the winding 17 of relay device 14. To this end winding 17 has one terminal connected by a conductor 18 through a source of alternating current supply 19 to the filament 20 01 the electric valve and the other terminal connected to the plate 21 of the electric valve. The filament heatingcircuit is indicated at 22. Grid 23 is connected-by a conductor 24 to a point between the variable condenser A and the fixed condenser 13. A resistance 25 may be provided on this circuit to prevent high currents ing between the filament and the plate. When a vehicle passesover the vehicle actuated device, the plates 7 of the condenser are moved closer together due to the weight of the vehicle depressing the casing 8 thereby increasing the capacitance of the condenser A and efiecting an unbalance between the two condensers A and B in a direction such that positive voltage is applied to grid 23. Current will now flow in the plate circuit, energizing relay winding 17 and opening the circuit through conductor 15 to effect an actuation of the control mechanism for the signals 2.

As soon-as the pressure on the vehicle actuated device is released, negative voltage is again applied to grid 25 thereby stopping fiow of current in the plate circuit and deenergizing relay 14.

By my invention, I provide a vehicle actuated device which is simple in structure and entirely enclomd in a casing so as to be protected from the weather. Also, I avoid the use of contacts which must be moved into engagement with each other. This results in a vehicle actuated device Letters Patent oi the United States, is:

1. In combination, a vehicle-actuated device including a condenser mounted at a highway intersection in the path of vehicles and provided with plates resiliently mounted with respect to each other and arranged to change the capacity of said condenser when compressed by vehicles approaching said intersection, a traillcunit, and means responsive to such change in the capacity 01' said condenser for operating said signalling unit for indicating the right of way to vehicles causing said change in capacity.

2. In combination, a traillc-signalling unit arranged to control traffic at the intersection of a plurality of tramc lanes, vehicle-responsive means located in each oi said trafllc lanes including a condenser arranged to change its capacity when compressed by a vehicle, and means responsive to said change in capacity including an electric-discharge valve connected. between said condenser and said signalling unit to operate said signalling unit to sive the right of way to the lane 01' said condenser.

JUSTIN PETERSON- 

